1. Field of the Invention
The present invention relates generally to electronic recognition and identification systems for identifying electrically coded objects and more particularly, to a system including an electrical network adapted to respond to the frequency of coded electrical resonant circuits in the form of master keys.
2. Description of the Prior Art
Electronic recognition and identification systems, such as the common lock and key system, presently exist for performing various functions relative to portal control. For example, an individual may carry an electrically coded identification card (key) for presentation to a reading station when the individual desires to enter into a door. If the card carries an appropriate code, responsive identification control signals are generated which in turn permit the opening of the door.
In another application, an object may carry an identification card electrically coded to identify the object. As the card passes a reading station, the code is read and responsive identification control signals are generated. The identification signals may accordingly be utilized to control associated object processing equipment, or if the object is in transit, the destination of the object.
Examples of prior electronic recognition and identification systems may be found in U.S. Pat. No. 3,752,960, entitled "Electronic Identification and Recognition Systems"; U.S. pat. application entitled "Improved Electronic Recognition and Identification System" filed May 25, 1973, Ser. No. 363,851 by Charles A. Walton and assigned to the assignee of the present application; and U.S. Pat. No. 3,842,246, entitled "Recognition and Identification System with Noise Rejection Capabilities" by Robert D. Kohler, David P. Sidlauskas, and Charles A. Walton, and assigned to the assignee of the present application. U.S. Pat. No. 3,732,465 describes an electronic sensing and actuator system.